Fate of sulfonamides in wetland systems by multi-element stable isotope concept

Project Information

FATE-SA

Grant agreement ID: 101108336

DOI

10.3030/101108336

Project closed

EC signature date 20 April 2023

Start date 1 October 2023

End date 30 September 2025

Funded under

• Marie Skłodowska-Curie Actions (MSCA)

Total cost

No data

EU contribution

€ 211 754,88

Coordinated by

CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE CNRS
France

Periodic Reporting for period 1 - FATE-SA (Fate of sulfonamides in wetland systems by multi-element stable isotope concept)

Reporting period: 2023-10-01 to 2025-09-30

Summary of the context and overall objectives of the project

Sulfonamide antibiotics (SAs) are essential medicines used in human and veterinary care. However, their widespread use and incomplete removal in conventional wastewater treatment plants lead to their release into the environment. This contamination promotes the development and spread of antibiotic-resistant bacteria and genes, a major global health threat identified by the World Health Organization. Constructed wetlands are a natural, cost-effective technology used to clean wastewater, but the specific processes by which they break down antibiotics like SAs are not fully understood, making it difficult to optimise their design and efficiency.

The EU-funded FATE-SA project addressed this critical knowledge gap. Its primary objective was to develop and validate a novel scientific tool to precisely track and quantify the degradation of sulfonamide antibiotics in complex environmental systems like wetlands. The project pioneered the use of a multi-element stable isotope "fingerprinting" technique. The core idea is that as antibiotic molecules break down, the bonds between different atoms (Carbon, Hydrogen, Nitrogen, Sulfur) are broken, subtly changing their isotopic composition. By measuring these changes simultaneously—a first for this class of antibiotics—the project aimed to act as an environmental detective, identifying not only if the antibiotic is degrading but also how and to what extent. The ultimate goal was to provide a robust scientific basis for improving wetland systems, thereby contributing to cleaner water, a healthier environment, and the global fight against antimicrobial resistance.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

Over its 24-month duration, the FATE-SA project successfully executed a comprehensive research plan. The work began with the crucial development and optimisation of laboratory methods to extract SAs from various environmental samples (water, soil, plants) without altering their intrinsic isotopic "fingerprint," and to measure these fingerprints with high precision.

Using these validated methods, the project then conducted a series of laboratory experiments to simulate the key degradation processes occurring in wetlands. This included studying the breakdown of a model antibiotic, Sulfamethoxazole, by direct and indirect sunlight (photolysis) and by chemical reactions with common wetland components. For each process, the project precisely quantified the unique isotopic fingerprint, creating a reference library.

Furthermore, advanced chemical analysis techniques were used to identify the breakdown products formed during these degradation experiments. By linking the specific products to the corresponding isotopic fingerprints, the project confirmed the underlying molecular mechanisms of antibiotic breakdown. A field investigation in a real wetland system was initiated, where samples were collected to later test the application of the laboratory-derived method in a natural setting. The core analytical work on these field samples is planned for the immediate future.

The main achievements include: the successful establishment of the first four-dimensional isotope fingerprinting method for SAs; the creation of a comprehensive database of isotopic signals for different degradation pathways; and the identification of key breakdown products, significantly advancing our understanding of antibiotic fate in the environment.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The FATE-SA project delivered significant advancements beyond the current state of the art. It developed the first-ever four-dimensional (C, H, N, S) isotopic framework for tracking sulfonamide antibiotics in the environment. This multi-element approach provides a much more powerful and reliable diagnostic tool than previous single-element methods, allowing researchers to distinguish between different degradation pathways (e.g. sunlight-driven vs. plant-assisted breakdown) that were previously difficult to tell apart.

The project generated a validated, publicly available dataset of isotopic fingerprints, providing the scientific community with a new tool to monitor antibiotic removal and persistence in various ecosystems, not just wetlands. This knowledge is critical for designing more effective wastewater treatment systems. For instance, understanding that indirect photolysis is a major degradation pathway could lead to optimised wetland designs that enhance this natural process.

The potential impacts are substantial. By enabling better monitoring and management of antibiotic pollution, the project directly supports the EU's strategic goals for a zero-pollution environment and contributes to the UN Sustainable Development Goals for clean water (SDG 6) and life on land (SDG 15). The methodologies are scalable and can be adapted to track other emerging micropollutants, such as pesticides or pharmaceuticals. To ensure further uptake, the next steps involve applying the method in full-scale wetland systems and promoting its adoption by environmental agencies and consulting firms for water quality assessment and the mitigation of environmental antibiotic resistance.